One method of forming a thin sheet of glass is by a drawing process where a ribbon of glass is drawn from a reservoir of molten glass. This may be accomplished, for example, via a down-draw process (e.g. slot or fusion), where the ribbon is drawn downward, typically from a forming body. Once the ribbon is formed, individual sheets of glass are cut from the ribbon.
In a conventional downdraw process, the molten glass is formed by melting precursor, or batch materials in a melting furnace. The molten glass is then flowed through various other components, such as fining vessels and stirring vessels. Eventually, the molten glass is conveyed to the forming body where the molten glass is formed into a continuous ribbon of glass. The ribbon may thereafter be separated into individual panes or glass sheets. The transfer apparatus for molten glass from the upstream portions of the conveying system to the forming body is particularly important, and must be capable of balancing many needs, such as the thermal expansion of the different materials of the system. For example, in the case of a fusion-type downdraw process, the forming body is typically a refractory material (e.g. a ceramic), that has a different thermal expansion characteristic than the principally platinum or platinum alloy vessels preceding it. To that end, the connection between the preceding system and the forming body inlet are typically free-floating, in the sense that the inlet conduit and the feed conduit are not directly joined, but instead ride one within the other without direct contact. Nevertheless, there is a need to provide a seal between the feed and inlet conduits.